Machine suitable for placing a component on a substrate, as well as a method therefor

ABSTRACT

Machine ( 1 ) comprising a placement element ( 7 ) connected to an imaging device ( 6 ), and comprising an optical system ( 4 ) for detecting the position of a component ( 16 ) relative to the placement element ( 7 ) by means of the imaging device ( 6 ). The optical system ( 4 ) comprises at least one marking element ( 11 ). The marking element ( 11 ) and the component ( 16 ) can be displayed simultaneously by means of the optical system ( 4 ) in an image ( 17 ) to be made by means of the imaging device ( 6 ).

The invention relates to a machine suitable for placing a component on asubstrate, the machine comprising an imaging device, a placement elementconnected to the imaging device, as well as an optical system fordetecting the position of the component supported by the placementelement by means of the imaging device.

The invention also relates to a method for placing a component on asubstrate by means of a machine, the component being picked up by meansof a placement element, then, by means of an imaging device and anoptical system, an image being made of the component picked up by meansof the placement element, after which the component is placed on thesubstrate.

In such a machine and method known from international patent applicationWO 97/22237, a component is picked up by a placement element and thentaken to a position located above an optical system. By means of theoptical system the component is displayed in the imaging deviceconnected to the placement element. From the image made by means of theimaging device, the position of the component relative to the placementmachine is determined after which the component is placed in a desiredposition on a substrate.

A disadvantage of the known machine is that the placement element andthe imaging device connected thereto are to be positioned accuratelyrelative to the optical system to be able to accurately determine theposition of the component relative to the placement element.

In addition, the position of the component relative to the opticalsystem connected to the fixed world cannot be accurately determined inthis manner.

It is an object of the present invention to provide a machine by whichthe position of the component can be determined accurately andrelatively rapidly.

This object is achieved by the machine according to the invention inthat the optical system comprises at least a marking element, in which,in operation, the marking element and the component can be displayedsimultaneously by means of the optical system in an image to be made bymeans of the imaging device.

Since both the component and the marking element connected to theoptical system are visible in the image and the position of the markingelement relative to the optical system is accurately known, the positionof the component relative to the optical system at the time when theimage is made can be determined accurately from the image. In addition,if the position of the placement element at the time of the image madeis also known, also the position of the component relative to theplacement element can be determined.

Furthermore, by means of the imaging device it is possible to produce animage of part of a substrate so as to determine the desired positioningspot of the component on the substrate.

Once the relative positions of a component and a substrate are knownfrom the two images, the component can be placed on the desired spot onthe substrate.

An embodiment of the machine according to the invention is characterizedin that the machine comprises at least a calibration marking element, inwhich the marking element is located in a first focal plane whereas thecalibration marking element is located in a second focal plane, whichmarking elements, in operation, can be displayed simultaneously in animage to be made by means of the imaging device.

When the image is made, the calibration marking element is located inpredetermined positions relative to the optical system. On the basis ofthis a certain mutual position between the marking element and thecalibration marking element is expected in the image. If deviations thenoccur, the optical system and the imaging device should be checked andcorrected until the calibration marking element in the image has anexpected position relative to the marking element. Alternatively it ispossible to take the deviations established into account when thecomponent is placed on the substrate.

A further embodiment of the machine according to the invention ischaracterized in that the placement element comprises a marking elementconnected to the placement element, which marking element, in operation,can be displayed simultaneously with the component in an image made bymeans of the imaging device.

When the image of the component is made by means of the imaging device,the position of the placement element need not be known. Since theplacement element and the connected marking element and the imagingdevice are interconnected, the marking element connected to theplacement element is located in a predefined and fixed position relativeto the imaging device. From the image made by the imaging device, inwhich image the marking element, the component and the marking elementconnected to the placement element can be displayed simultaneously, theposition of the component and of the placement element relative to theoptical system can be accurately determined. In this way both theposition of the component relative to the “fixed world” and the positionof the component relative to the placement element can thus bedetermined.

Yet a further embodiment of the machine according to the invention ischaracterized in that the marking element connected to the placementelement can be optically displayed in a plane in which there is acomponent during operation.

In this fashion the marking element connected to the placement elementis not physically in the plane in which the component is located, sothat the marking element will not collide with the substrate when thecomponent is placed on the substrate. Since the marking element canindeed be optically displayed in this plane, both the component and themarking element will be clearly visible in the image.

Yet a further embodiment of the machine according to the invention ischaracterized in that the imaging device comprises a marking elementconnected to the imaging device, which marking element, in operation,can be displayed simultaneously with the marking element connected tothe optical system in an image made by means of the imaging device.

The marking element connected to the imaging device will have apredefined position in the image. If, however, some deviations do occur,this may be an indication that the imaging device does not operateproperly and is to be checked.

The invention also relates to a method for placing a component on asubstrate by means of the machine, with which in a simple and relativelyfast manner the position of a component relative to a placement elementcan be determined.

This object is achieved with the method according to the invention inthat in the image a marking element connected to the optical system aswell as the component is displayed after which the position of thecomponent relative to the optical system is determined by means of themarking element.

From the image can therefore be determined in an accurate and fastmanner the position of the component relative to the marking element andtherefore relative to the optical system.

An embodiment of the method according to the invention is characterizedin that a further image is made by means of the imaging device, fromwhich further image the desired position of the component on thesubstrate is determined, after which the component is placed on thedesired position.

The position of the substrate relative to the imaging device isdetermined from the further image. From the two images the position ofthe component relative to the substrate can be determined, after whichthe component is placed in the desired position on the substrate bymeans of the placement element.

These and other aspects of the invention are apparent from and will beelucidated with reference to the embodiments described hereinafter.

In the drawings:

FIG. 1 shows a perspective view of a machine according to the invention,

FIG. 2 shows a diagrammatic side elevation of part of a first embodimentof the machine shown in FIG. 1,

FIG. 3 shows an image produced by means of the device shown in FIG. 2,

FIG. 4 shows a diagrammatic side elevation of part of a secondembodiment of the machine shown in FIG. 1,

FIG. 5 shows an image produced by means of the machine according to theinvention shown in FIG. 4,

FIG. 6 shows a diagrammatic side elevation of part of a third embodimentof the machine shown in FIG. 1,

FIG. 7 shows an image made by means of the device shown in FIG. 6,

FIG. 8 shows a diagrammatic side elevation of part of a fourthembodiment of the machine shown in FIG. 1,

FIG. 9 shows an image produced by means of the device shown in FIG. 8,

FIG. 10 gives a diagrammatic side elevation of part of a fifthembodiment of the machine shown in FIG. 1,

FIG. 11 shows an image made by means of the device shown in FIG. 10.

Like components in the Figures have like reference characters.

FIG. 1 shows a machine 1 according to the invention, which comprises aframe 2, transport rails 3 supported by the frame 2, an optical system 4positioned on the side of the transport rails 3 and a unit 5 that ismovable above the transport rails 3 and the optical system 4, an imagingdevice 6 and a placement element 7 together being connected to themovable unit 5. The unit 5 can be moved in and opposite to the directionindicated by the arrow X relative to a slide 8. The slide 8 can be movedin and opposite to the direction indicated by the arrow Y relative to aU-shaped frame 9. The U-shaped frame 9 rests with two legs 10 on theframe 2.

The machine described thus far is known per se, for example frominternational patent application WO 97/22237 mentioned in the openingparagraph.

The optical system 4 of the machine 1 according to the inventioncomprises a marking plate 12 (see FIGS. 2, 4, 6, 10) with markingelements 11. The marking plate 12 is preferably made of glass in which,for example, square marking elements 11 are provided.

The marking plate 12 extends in parallel with an X, Y plane. A firstreflecting element 13 arranged at an angle of 45% relative to thevertical is positioned underneath the marking plate 12. The opticalsystem 4 further comprises a second reflecting element 14 which alsoencloses a 45% angle to the vertical. A lens 15 is inserted between thereflecting elements 13, 14.

As FIG. 2 shows, a first focal point f1 is located in a first focalplane V1 which extends through the marking plate 12 when the imagingdevice 6 has the position relative to the optical system 4, whichposition is shown in FIG. 2. The lens 15 provides a second focal pointf2 which is located in a focal plane V2 which extends in parallel withthe first focal plane V1. As is shown in FIG. 2 the placement element 7with a component 16 attached thereto and with the position of theimaging device 6 shown therein, is located such that the second focalplane V2 extends through the component 16.

If an image is made by means of the imaging device 6, an image 17 shownin FIG. 3 is obtained in which both the marking elements 11 and thecomponents 16 are simultaneously visible. Since the positions of themarking elements 11 relative to the optical system 4 and, therefore,relative to the frame 2 are known, the position of the component 6relative to the marking elements 11 and therefore relative to the frame2 can be determined from the image shown in FIG. 3. The unit 5 is drivenby means of a driving unit (not shown) by means of which the actualposition of the frame 5 and therefore of the placement element 7relative to the frame is known at any moment, thus also at the momentwhere the image 17 is made. Therefore, the mutual position of thecomponent 16 relative to the placement element 7 can be derived from theposition of the placement element 7 relative to the frame 2 and theposition of the component 16 relative to the frame 2.

By means of the camera 6 an image can also be made of a substrate 18supported by the transport rails 3 (FIG. 1). From the two images canthen be determined in what way the unit 5 is to be driven to be able toplace the component 6 supported by the placement element 7 on thedesired position 19 on the substrate 18.

FIG. 4 shows a second embodiment of a machine 1 according to theinvention which comprises, in addition to the component parts shown inFIG. 2, a calibration marking plate 21 which includes calibrationmarking elements 20. The calibration marking plate 20 is preferably madeof glass. The calibration marking plate 20 is detachably positioned onthe optical system 4 by means of a support block 22, the second focalplane V2 extending through the calibration marking plate 20. To avoidcollision between the placement element 7 and the calibration markingplate 20, the placement element 7 is moved in the upward directionindicated by the arrow Z.

If an image is made by means of the imaging device 6, the image 23 shownin FIG. 5 is obtained in which the marking elements 11 and thecalibration marking elements 21 are simultaneously visible. Since boththe marking elements 11 and the calibration marking elements 21 have apredetermined position relative to the optical system 4 and the frame 2,in the event of a deviation in the image 23 between the expected andreal mutual positions of the marking elements 11 and the calibrationmarking elements 21, there may be derived that the imaging device 6and/or the optical system 4 does not function optimally and is thereforeto be checked.

It is alternatively possible to take the differences found into accountinstead when the component is placed on the substrate.

Therefore, the mutual positions of the focal point f1 located in thefirst focal plane V1 and the focal point f2 located in the second focalplane V2 are determined and checked by means of the calibrationelements.

Once the calibration marking elements 21 and the marking elements 11have a mutually desired position in the image 23, the block 22 and thecalibration marking plate 20 connected thereto can be removed. Thecalibration can again be carried out at any point of time desired by theuser.

FIG. 6 shows a third embodiment of a machine 1 according to theinvention which, in addition to the elements shown in FIG. 2, comprisestwo pins 24 extending in parallel with the placement element 7, whichpins are connected to one end to the unit 5 and with ends turned awayfrom the unit 5 are located in the second focal plane V2.

If an image is made by means of the imaging device 6, the image 25 shownin FIG. 7 is obtained. In the image 25 are simultaneously visible themarking elements 11, the component 16 and the pins 24 connected to theunit 5. From the image 25 can therefore be derived not only the positionof the component 16 relative to the marking elements 11 and thusrelative to the frame 2 but, in addition, the position of the unit 5 andthe connected placement element 7 can be derived from the positions ofthe pins 24 relative to the marking elements 11. In this way theposition of the unit 5 need not be measured separately when the image ismade, but can be directly derived from the image 25.

FIG. 8 shows a fourth embodiment of a machine 1 according to theinvention, which machine distinguishes itself from the machine shown inFIG. 6 in that in lieu of pins 24 use is made of two markings 26 whichare displayed in the second focal plane V2 as marking elements 26′ via alens 27. When an image 7 is made by the imaging device 6, image 28 shownin FIG. 9 is obtained, in which the marking elements 11, the components16 and the virtual marking elements 26′ are simultaneously visible. Fromthis image 28 can again be derived both the position of the component 16and the position of the unit 5 and the connected placement element 7relative to the frame 2. The machine shown in FIG. 8 is advantageous inthat when the component 16 is placed on the substrate 18 the markingelements 26 cannot collide with the substrate 18 or components alreadyplaced thereon. This risk does occur with the machine with the pins 24shown in FIG. 6. This risk may also be avoided if the component 16 ismoved in downward direction relative to the pins 24 when the component16 is placed on the substrate.

FIG. 10 shows a further embodiment of the machine 1 according to theinvention which, in addition to the elements present in FIG. 6 or 8,comprises a marking plate 29 connected to the imaging device 6, whichmarking plate includes marking elements 30. The marking plate 29 ispreferably made of glass. When the image is made by the imaging device6, the image 31 shown in FIG. 11 is obtained in which both markingelements 11, the component 16, the marking elements 24, 26′ and themarking elements 30 are visible. From this image 31 both the position ofthe component 16 relative to the frame 2 and the position of the unit 5relative to the frame 2 can be checked while in addition the correctfunctioning of the imaging device 6 can be derived from the mutualpositions of the marking elements 30 and the marking elements 11. Thesemarking elements 11, 30 should have a predetermined mutual positionrelative to each other. If deviations occur, this points at deviationsin the imaging device 6 after which the imaging device 6 is to bechecked or this should be taken into account when the unit 5 is driven.

Alternatively, it is possible to manufacture the marking plate of aplastic transparent material.

In lieu of the one lens 15 it is also possible to use a number oflenses. A lens may also be positioned between the marking plate and areflecting element. The angles of the reflecting elements may be smalleror larger than 45%. The angles together are preferably 90%. The focalplanes V1 and V2 are preferably at the same level as the substrate.

1. A machine suitable for placing a component on a substrate, themachine comprising an imaging device, a placement element connected tothe imaging device, as well as an optical system for detecting theposition of the component supported by the placement element by means ofthe imaging device, characterized in that the optical system comprisesat least a marking element, in which, in operation, the marking elementand the component can be displayed simultaneously by means of theoptical system in an image to be made by means of the imaging device. 2.A machine as claimed in claim 1, characterized in that the machinecomprises at least a calibration marking element, in which the markingelement is located in a first focal plane whereas the calibrationmarking element is located in a second focal plane, which markingelements, in operation, can be displayed simultaneously in an image tobe made by means of the imaging device.
 3. A machine as claimed in claim1, characterized in that the placement element comprises a markingelement connected to the placement element which marking element, inoperation, can be displayed simultaneously with the component in animage made by means of the imaging device.
 4. A machine as claimed inclaim 3, characterized in that the marking element connected to theplacement element can be optically displayed in a plane in which thereis a component during operation.
 5. A machine as claimed in claim 1,characterized in that the imaging device comprises a marking elementconnected to the imaging device, which marking element, in operation,can be displayed simultaneously with the marking element connected tothe optical system in an image made by means of the imaging device.
 6. Amethod for placing a component on a substrate by means of a machine, thecomponent being picked up by means of the placement element, then bymeans of an image device and an optical system an image being made ofthe component picked up by the placement element, after which thecomponent is placed on the substrate, characterized in that in the imagea marking element connected to the optical system as well as thecomponent is displayed after which the position of the componentrelative to the optical system is determined by means of the markingelement.
 7. A method as claimed in claim 6, characterized in that afurther image is made by means of the imaging device, from which furtherimage the desired position of the component on the substrate isdetermined, after which the component is placed in the desired position.8. A method as claimed in claim 6, characterized in that the machinecomprises a calibration marking element, in which the marking element islocated in a first focal plane, whereas the calibration marking elementis located in the second focal plane, which marking elements, inoperation, can be displayed simultaneously in an image to be made bymeans of the imaging device.
 9. A method as claimed in claim 6,characterized in that the placement element comprises a marking elementrigidly connected to the placement element, which marking element, inoperation, can be displayed simultaneously with the component in animage made by means of the imaging device.
 10. A method as claimed inclaim 6, characterized in that the imaging device comprises a markingelement connected to the imaging device which marking element, inoperation, is displayed simultaneously with the marking elementconnected to the optical system in an image made by means of the imagingdevice.